Locomotive draft appliance



April 16, 1935.

A. GlEsL-GIESLINGEN LOCOMOTIVE DRAFT APPLIANCE Filedma'rch 1, 1934 2sheets-sheet 1 April 16, 1935. A. GIESL-GIESUNGEN 3,998,008 l LOCOMOTIVEDRAFT PPLINCE Filed March l, 1934 2 Sheets-Sheet 2 mwN-ma,

M www Patented Apr. 16, 1935' UNITED STATES PATENT 4OFFICE LOCOMOTIVEDRAFT APPLIANCE Adolf Giesl-Gieslingen, New York, N. Application March1, 1934, Serial No. 713,552. 19 claims. (01.20-96) My present inventionrelates to steam locomotives wherein the draft required for the fire iscreated by suction obtained from an exhaust steam jet acting in theso-called draft appliance.

In my co-pending application Serial No. 592,710, I have shown how draftappliances of maximum over-all efliciency may be constructed,-

It is a primary object of my invention to simultaneously obtain greatestefficiency and simplicity of such draft appliances. Another importantobject is to throw the products of combustion as forcibly as possibleupward while they are ejected from the smokestack. Further objects areminimum wear of the device and minimum frictional and dynamic resistancein the exhaust nozzle, as well as the creation of an exhaust nozzlewhich will eject a compact steam jet of, within reasonable limits, anydesired divergence. Other objects will appear in the course of thefollowing description.

In the drawings, Fig. 1 is a longitudinal vertical control sectionthrough a locomotive smokebox showing a preferred embodiment of myimproved draft appliance. Fig. 2 is a plan view of the exhaust nozzle inFig. l.

Fig. 3 is a diagrammatical sketch of my improved draft appliance, forthe purpose of explaining its various features and preferredproportions.

Fig. 4 is a plan view of a modified exhaust nozzle, otherwise similar toFig. 2.

Figures 5 to 7 are diagrammatical sketches of a draft appliance ofoblong area, Fig. 5 being a vertical central section, Fig. 6 a verticallongitudinal central section at a right angle to Fig. 5, and Fig. 7 ahorizontal section along the line 'l-l in Fig. 6. Fig.8 is a verticalcross section through an exhaust nozzle having diverging,

slot-like openings which I sometimes prefer to use in combination with adraft appliance ac cordingto Figures 5 to 7.

Figures 9 to l1 are diagrammatical sketches of a draft appliance whereinmy'improved exhaust nozzle is combined with an intermediate nozzle ofthe kind claimed in my co-pending application Serial No. 592,710, Fig. 9being a vertical central section through the draft appliance and Figures10 and 11 showing, respectively, the outlet configurations of theintermediate nozzle and the exhaust nozzle.

In spite of the great and continued attentionl that the locomotive draftappliance is receiving since about a century ago, no reliable rules'have been established for the factors promoting efficient draftproduction, nor has the action of the steam jet been adequatelyexplained. Two major principles are being advocated in the design ofdraft appliances: -the first and less frequently mentioned may be calledthe Venturitube principle of which U. S. patent to Bruce, No. 1,853,893is a recent example. The underlying idea is that better entrainment isobtained if the steam jet acts upon a concentrated body of gas, that iswithin a considerably restricted cross-sectional area of the smokestack,and therefore the latter is of double conoidal form with a narrow throatabove the nozzle opening. A compact steam jet is employed, flowing froma plain, undivided nozzle opening. l

The second, an entirely different lprinciple according to which draftappliances are designed, is that of providing a large contact surfacebetween the steam jet and the gases with a View to increasingentrainment by what is commonly called frictional action. A recentexample may be found in U. S. patent to Kiesel, No. 1,749,487, where anexhaust nozzle having a star-shaped outlet opening is used, whereby thenozzle diameter is large relative to its area. The large circumferencelof the steam jet makes the use of a relatively wide stack necessary, andthe result is a low speed of the mixture of gas and steam escaping fromthe stack outlet, and consequently a tendency of the smoke to trail downto the locomotive cab.

More moderate use of the above-mentioned second principle of providing alarge contact surface is made in the more generally applied draftappliances, wherein either relatively short smokestacks are provided inorder to freely expose to the gases a large portion of the steam jet, orthe steam is split by bridges and the like, combined with longersmokestacks contain ing no or moderate restrictions compared with theiroutlet area. The practices are very varied and confused, without muchapparent advantage of one over the other and with much left to bedesired in efficiency of draft production.

It appears that those who were concerned about providing a steam jetwith a large Contact surface forgot about or felt forced to disregardthe contradicting Venturi principle, while those, if any, who advocatedthe Venturi principle and consequently sought to employ a compact steamjet, found it impossible to employ a smokestack of adequate dimensions,because a compact steam jet would, in the relatively restricted space ona large locomotive, fill only a relatively extremely narrow stack, andwould not follow an outlet taper of more than about 1 in 7, resulting insuch excessive speed of the gases escaping from the stack with theaccompanying energy loss that no benefit whatever would result. In fact,the Venturi principle has not found practical application in modernlocomotives.

I have discovered that, if the Venturi principle is correct, and if 'itsadvantages outweigh those of a large contact surface of the steam jet,then a sharply tapering, double conoidal stack which will permit thedesired outlet area to be reached within the restricted height availableon the locomotive must be advantageous if a compact steam jet can beproduced with a taper corresponding to that of the stack in order to llthe same in the desired manner, andI succeeded in devising sucharrangements of greater efficiency' than any known simple draftappliances, as will now be described:

yFigures 1 and 2 show a preferred embodiment of my invention. The boilerbarrel I, closed by the tube sheet 2 in which the fiues 3 terminate, isattached to the smokebox 4. The draft appliance consists of thesmokestack 5, the stack extension 6, the basket I and the exhaust nozzle8, all preferably secured together to form a self-contained unit andsuspended from the saddle 9 in the manner described and claimed in myco-pending application Serial No. 655,161. The exhaust standpipe I isheld in fixed relation to the smokebox and reaches into the annularspace formed between the downward extension II of the exhaust nozzle 8and the lower ring I2 ofthe basket 1. Thus the exhaust steam isdischarged into the nozzle 8. The circumferential walls of the nozzle 8are preferably diverging toward its outlet as illustrated, terminatingin theoutlet plane I3-I3. Radial, wedge-shaped partitions I4 definepreferably four steam passages I5 the center lines I6 of which divergewith respect to the central axis I'I of the exhaust nozzle andsmokestack in such a way that four steam jets with the contours I8, I9are formed, each substantially a quarter circle in cross section, and sodirected that they form a compact jet as soon as possible as theyexpandwhile on their way upward, preferably filling the throat 2l) ofthe stack as indicated, and continuing to fill the stackup to itsYoutlet 2I.

Referring to the diagrammatical sketch Fig. 3, the various preferredproportions of my invention will be further discussed with a view toserving as a guide for practical design. Like numerals are used forcorresponding parts. 'I'he outlet diameter A vof the stack should bechosen with a view to obtaining suicient lifting power of -the exhaustto prevent trailing Whenever practicable. The nozzle diameter C followsfrom the expected nozzle outlet area, to which the required area of thepartitions must be added. The latter depends upon the necessaryspreading effect and, therefore, upon the divergence of the hypotheticalcone 22 connecting the circumference of the exhaust nozzle with the topof the stack, and the proper relation is to be found from experience. Asatisfactorily compact steam iet will not be Obtained if the aggregatecross-sectional area of the spaces between the individual jets isgreater than the aggregate outlet area of the nozzle, and for bestresults said relation should be nearer forty to sixty per cent which issuicient in practice to obtain properly sized stacks. For greaterspreading the number of the radial partitions may be l increased toabout 6, for smaller spreading it may be reduced to v3 but not less. Thepartitions I4 may of course also end flush with the outer wall of theexhaust nozzle, without extending beyond plane I3-I3. The choke diameterB of the stack should be such as to give a minimum cross sectional areaof between forty and fifty-five per cent of the stack outlet area -at2l, preferably nearer the average of these figures and not much lessthan 4 or 5 times the outlet area of the exhaust nozzle. The stackextension 6 may be of various aring shapes without much effect upon theefficiency of the draft appliance, provided that a proper inlet area beoffered to the gases between the exhaust nozzle and the stack inlet.'Ihe latter factor is of decisive importance as the Venturi shape of thestack would become ineffective if the inlet were so placed as to permita large, slow-moving body of gas to come in contact with the steam jet.For the purpose of definition, I place into the stack inlet andtangentially touching the same, the hypothetical cone 23 having its apexin the central axis II of the draft appliance, and opening at an angleof 60 degrees, and I define as inlet area the conoidal surface F formedbetween the said cone 23 and the circumference of the exhaust nozzle inthe manner indicated in Fig. 3. Said inlet area should be about half-waybetween twenty per cent and fifty per cent of the free gas passagewithin the boiler fiues, and for the above explained reason, shouldalways be smaller than said gas passage. For similar reasons, the totallength E of the stack should be great, and more than seventy or bettermore than eighty per cent of the distance D between the outlet of theexhaust nozzle and the top of the stack. The afore-mentionedrecommendations will enable those skilled in the art to put my inventioninto practice.

While I prefer to shape the partitions in my exhaust nozzle as shown atI4 in Figures 1 to 3, the modification illustrated in Fig. 4 may also beused without departing from the spirit of my invention. In saidmodification, the radial ribs 24 do not merge in the center but end at ashort distance therefrom, defining the principal passages I5 havingdiverging center lines, and communicating with the central passage 25.HoweverI do not recommend this form for obvious reasons.

Whether the dividing members in the exhaust nozzle are .of the forms 24or I4, an essential feature is that they extend far enough axially togive practically every particle of the escaping steam the desireddiverging direction; and to this end I give `said dividing members asmallest axial dimension preferably double or at least equal to themaximum diametrical dimension of the passages defined between saiddividing members; that is, I make the dimension H in Fig. 3 greater thanK in Fig. 2. In order that the steam may properly touch the confiningWalls, I give each one of the Vpassagesa. substantially constant areathroughout its length. I do not desire to contract the steam while owingthrough the passages because this would be contrary to the object ofobtaining a. greatly diverging jet, nor do I favor a' I the steam wouldthen not fully touch the vconfining walls and would not be properlyguided.

Smokestacks having an oblong cross-sectional area, with correspondinglyslot-like exhaust nozzle openings have heretofore been proposed with theprimary purpose of obtaining a steam jet with maximum entrainingsurface, yet they have not been regarded as successful. I havediscovered that highly eilicient draft appliances malr be created ifsuch oblong smokestacks are designed according to Venturi principles, asillustrated in Figures to 7. In my copending application Serial No.592,710, I have explained that one may regard an oblong draft applianceas being composed of a number of circular draft appliances correspondingto Fig. 5, all arranged in line and with their adjacent walls removed;

vthus the principles explained in connection with Fig. 3 may be appliedhere without requiring further discussion, and corresponding parts areindicated by like reference numbers. However, since the width A and thelength L of such oblong draft appliances may be chosen at will for anydesired outlet area, artificial spreading of the steam in the exhaustnozzle isusually not necessary, and the exhaust nozzle 26 may be formedwith a plain, slot-like opening as shown. If a relatively short length Land a consequently greater Width A is required, I employ an exhaustnozzle 21, Fig. 8, having a longitudinal partition 28 and circum"Aferential walls of such shape that two passages 29 are formed with theirlongitudinal central planes diverging in the direction of the flow asshownv in the cross-section.

Due to the peculiarities of oblong draft appliances, I preferito givethem aslightly wider throat and a relatively longer stack thanrecommended for circular devices, both increases being in the order offive per cent.

My improved exhaust nozzle may also be used with advantage in connectionwith a split intermediate nozzle of the general form claimed in myco-pending application Serial No. 592,710. A preferred combination isshown in Figures 9 to 11, wherein the intermediate nozzle-3| isinterposed between the exhaust nozzle 30 and the stack 32.

The partitions 33 -in the exhaust nozzle are situated in line with those34 in the intermediate nozzle whereby the exhaust channels 35 ejectsteam jets 36 corresponding to the channels 3'! in the intermediatenozzle; This arrangement enables a very gentle spreading to be used,whereby, in connection with a more correct fiow through the intermediatenozzle, energy losses are minimized; to this end I also prefer to give alesser angular divergence to the partitions 33 which are exposed to thehigher jet speed, and I give a greater angular divergence to thepartition 34 in the intermediate nozzle.

Having described my invention to enable those skilled in the art to`make and reproduce the same, I claim:

1. In a locomotive, a smokestack and an exhaust nozzle, and partitionsat the outlet of the said exhaust nozzle defining at least three steampassages, the geometric center lines of said steam passages divergingwith respect to the central axis of the nozzle in the direction of thesteam flow, said smokestack diverging toward its outlet and having aminimum cross-sectional area of more'than forty per cent but not morethan fifty-five per cent of its outlet area and having a length of atleast eighty per cent of the distance from the outlet of the exhaustnozzle to the outlet of the stack.

2. The combination claimed in claim 1, characterized thereby that thepartitions defining the said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage.

3. The combination claimed in claim 1, characterized thereby that thepartitions deiining the said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at la right angle to the center line ofthe steam passage, and further characterized thereby that the aggregatecross-sectional area of the spaces formed between the said steampassages is smaller than the agg'regate outlet area of the said steampassages; whereby a relatively compact steam jet of unlform divergenceis obtained.

4. Ina locomotive, a smokestack and an ex-` haust nozzle, and partitionsat the outlet of the f said exhaust nozzle defining at least three steampassages, the geometric center lines of said steam passages divergingWith respect to the central axis of the nozzle in the direction of thesteam ow, said smokestack diverging toward its outlet and having aminimum cross-sectional area of more than forty per cent but not morethan fifty-five per cent of its outlet area and having a. length of atleast eighty per cent of the distance from the outlet-of the exhaustnozzle to the outlet of the stack, and an inlet area for the combustiongases defined between the circumference of the exhaust nozzle and theinlet of the stack of at last two-tenths, but not more than one-half ofthe total gas passage within the boiler iiues.

5. The combination claimed in claim 4, characterized thereby that thepartitions defining the said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage.

6. The combination claimed in claim 4, characterized thereby that'thepartitions defining the said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage, and vfurther characterized thereby that the aggregatecrosssectional area of the spaces formed between the said steam passagesis smaller than the aggregatey outlet area of the said steam passages;whereby a relatively compact steam jet of uniform divergence isobtained.

7. In a locomotive, a smokestack and lan exhaust nozzle, and partitionsat the outlet of the said exhaust nozzle defining a plurality of steampassages, the geometric center lines of said steam passages divergingwith respect to the central axis of the nozzle in the direction of thesteam' flow, said smokestack diverging toward its outlet and having aminimum cross-sectional area said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage.

9. The combination claimed in claim 7, characterized thereby that thepartitions defining the said diverging steam passages of the saidexhaust nozzle have a. minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage, and further characterized thereby that the aggregatecrosssectional area of the spaces formed between the said steam passagesis smaller than the aggregate outlet area of the said steam passages;whereby a relatively compact steam jet of uniform divergence isobtained.

10. In a locomotive, a smokestack and an exhaust nozzle, and partitionsat the outlet of the said exhaust nozzle defining a plurality of steampassages, the geometric center lines of said steam passagesdivergingwith respect to the lcentral axis of the nozzle in thedirection of the steam flow, said smokestack diverging toward its outletand having a minimum cross-sectional area of not more than sixty percent of its outlet area and having a length of at least Iseventy percent of the distance from the outlet of the exhaust nozzle to the outletof the stack, and an inlet area for the combustion gases, dened betweenthe circumference of the exhaust nozzle and the inlet of the stack, ofless than the total lgas passage within the boiler fiues.

11. The combination claimed in claim 10, characterized thereby that thepartitions defining the said diverging steam passages of the saidexhaust nozzle have a minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage.

12. The combination claimed in claim 10, charaoterized thereby that thepartitions defining the said diverging steam passages of the saidexhaust nozzle have minimum axial length that is greater than themaximum diametrical dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage, and further characterized thereby that the aggregatecross-sectional area of the spaces formed between the said steampassages is smaller than the aggregate outlet area of the said steampassages; whereby a relatively compact steam jet of uniform divergenceisobtained.

13. In a locomotive, a smokestack having an oblong cross section, anexhaust nozzle offering to thesteam flow at least one elongated,slotlike outlet area, said stack diverging toward its staclz, of morethan two-tenths but not more than one half of the total gas passagewithin the boiler flues.

14. In a locomotive, a smokestaok having an oblong cross section, saidstack diverging toward its4 outlet and having a minimum cross-sectionalarea of not morethan sixty-five per cent of its outlet area.

15. In a locomotive, a smokestack having an oblong cross section and anexhaust nozzle oiering to the steam ow at least one outlet area, saidstack having an axial length in the direction of the steam flow of atleast seventy-five per` cent of the distance from the outlet of theexhaust nozzle to the outlet of the stack, and an inlet area for thecombustion gases, defined between the circumference of the exhaustnozzle and the inlet of the stack, of less than the total gas passagewithin the boiler flues.

16. In a locomotive, an exhaust nozzle having circumferential wallsdivering toward its outlet, and partitions at its outlet defining asmall number of steam passages, all of said passages having asubstantially constant cross-sectional area throughout their axiallength, the geometric center lines of said steam passages diverging withrespect to the central axis of the nozzle in the direction of the steamflow, the minimum axial length of said partitions being greater than themaximum diametrioal dimension of any such steam passage defined betweenthe respective partitions, taken at a right angle to the center line ofthe steam passage, and further characterized th'ereby that the aggregatecross-sectional area of the spaces formed between the said 'steampassages is smaller than the aggregate outlet area of the said steampassages.

17. In a locomotive, an exhaust nozzle having circumferential wallsdiverging toward its outlet, and partitions at its outlet defining asmall number of steam passages, all of said steam passages having asubstantially constant cross-sectional area throughout their axiallength, the geometric center lines of said steam passages diverging withrespect to the central axis of the nozzle in the direction of the steamfiow.

18. In a locomotive, an exhaust nozzle having an outside confining walldiverging toward the nozzle outlet and enclosing an oblong slot-likeoutlet area, and a longitudinally disposed wedgeshaped partitiondividing said outlet area and defining outlet passages diverging fromthe central plane of the said partition in the direction of the steamflow.

19. In a locomotive'a smokestack, an exhaust nozzle having radiallydisposed partitions definling a plurality of steamv passages, saidpartitions forming Wedges directed against the steam flow and splittingthe same; and an intermediate nozzle interposed between said exhaustnozzle and smokestack, said intermediate nozzle having similar radiallydisposed partitions situated in line with the said partitions in theexhaust nozzle and forming wedges having a larger apex than thecorresponding wedges in the exhaust nozzle.

ADOLF GIESL-GIESLINGEN.

